[FFmpeg-devel] [RFC] clobbers for XMM registers

[Måns Rullgård]

Michael Niedermayer <michaelni at gmx.at> writes:

> On Mon, Sep 27, 2010 at 09:15:24PM -0400, Ronald S. Bultje wrote:
>> Hi,
>> 
>> 2010/9/27 M?ns Rullg?rd <mans at mansr.com>:
>> > Michael Niedermayer <michaelni at gmx.at> writes:
>> >> On Tue, Sep 28, 2010 at 01:51:33AM +0200, Michael Niedermayer wrote:
>> >>> On Sat, May 29, 2010 at 08:27:58PM +0200, Reimar D?ffinger wrote:
>> >>> > Hello,
>> >>> > this is not suitable by far (among other things, ugly parts, split asm code
>> >>> > where a clobber is likely to introduce bugs, only tested to compile,
>> >>>
>> >>> > did not find a nice "dummy" clobber constraint - particularly important since
>> >>>
>> >>> try "%esp" ;)
>> >>>
>> >>>
>> >>> > I suspect older gccs won't accept %xmm clobbers, ...).
>> >>>
>> >>> the oldest i have here is 3.3 and it supports it
>> >>
>> >> has someone tested xmm clobbers on fate alraedy?
>> >> if not i think we should commit one and see what fails
>> >> then we can decide if we need a macro wraping them at all
>> >
>> > We tested. ?It failed.
>> 
>> See r24931 and r24934 in vp3dsp_sse2.c.
>> 
>> http://archives.free.net.ph/message/20100825.195706.b4de9543.en.html
>> http://archives.free.net.ph/message/20100825.203635.00f52a36.en.html
>
> do you happen to remember the error messages and which compiler version
> was affected?

All BSD and all Windows.  See for example
http://fate.ffmpeg.org/x86_32-dragonflybsd-gcc-4.1.2/20100825202620
http://fate.ffmpeg.org/i686-pc-mingw32-gcc-4.2/20100825201526

libavcodec/x86/vp3dsp_sse2.c:165: error: unknown register name '%xmm7' in 'asm'

-- 
M?ns Rullg?rd
mans at mansr.com